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Rotational Frequency
Rotational frequency, also known as rotational speed or rate of rotation (symbols ''ν'', lowercase Greek nu, and also ''n''), is the frequency of rotation of an object around an axis. Its SI unit is the reciprocal seconds (s−1); other common units of measurement include the hertz (Hz), cycles per second (cps), and revolutions per minute (rpm). Rotational frequency can be obtained dividing ''angular frequency'', ω, by a full turn (2 π radians): ''ν''ω/(2πrad). It can also be formulated as the instantaneous rate of change of the number of rotations, ''N'', with respect to time, ''t'': ''n''d''N''/d''t'' (as per International System of Quantities). (11 pages) Similar to ordinary period (physics), per ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rotation (aeronautics)
In aviation, rotation refers to the action of applying back pressure to a control device, such as a yoke, side-stick or centre stick, to lift the nose wheel off the ground during takeoff. An aircraft moves at any given moment in one or more of three axes: roll (the axis that runs the length of the fuselage), pitch (the axis running laterally through the wings), and yaw (the vertical axis around which the front of the aircraft turns to the left or right whilst its rear turns toward the opposite direction). Displacement along any of these axes is a form of rotation, but the term "rotation" in relation to takeoff is limited to the moment during which the aircraft's nose rises from the ground: the aircraft rotates around its lateral axis. The first critical speed during takeoff (at which a pilot must decide whether to continue with takeoff or abort it) is called the "decision speed", or V1, beyond which it would be unsafe to abort the takeoff. Rotation is begun at the speed known ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angular Frequency
In physics, angular frequency (symbol ''ω''), also called angular speed and angular rate, is a scalar measure of the angle rate (the angle per unit time) or the temporal rate of change of the phase argument of a sinusoidal waveform or sine function (for example, in oscillations and waves). Angular frequency (or angular speed) is the magnitude of the pseudovector quantity '' angular velocity''. (UP1) Angular frequency can be obtained multiplying '' rotational frequency'', ''ν'' (or ordinary ''frequency'', ''f'') by a full turn (2 radians): . It can also be formulated as , the instantaneous rate of change of the angular displacement, ''θ'', with respect to time, ''t''. (11 pages) Unit In SI[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angular Acceleration
In physics, angular acceleration (symbol α, alpha) is the time rate of change of angular velocity. Following the two types of angular velocity, ''spin angular velocity'' and ''orbital angular velocity'', the respective types of angular acceleration are: spin angular acceleration, involving a rigid body about an axis of rotation intersecting the body's centroid; and orbital angular acceleration, involving a point particle and an external axis. Angular acceleration has physical dimensions of angle per time squared, measured in SI units of radians per second squared (rads−2). In two dimensions, angular acceleration is a pseudoscalar whose sign is taken to be positive if the angular speed increases counterclockwise or decreases clockwise, and is taken to be negative if the angular speed increases clockwise or decreases counterclockwise. In three dimensions, angular acceleration is a pseudovector. Orbital angular acceleration of a point particle Particle in two dimensions ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Revolution (geometry)
In political science, a revolution (, 'a turn around') is a rapid, fundamental transformation of a society's class, state, ethnic or religious structures. According to sociologist Jack Goldstone, all revolutions contain "a common set of elements at their core: (a) efforts to change the political regime that draw on a competing vision (or visions) of a just order, (b) a notable degree of informal or formal mass mobilization, and (c) efforts to force change through noninstitutionalized actions such as mass demonstrations, protests, strikes, or violence." Revolutions have occurred throughout human history and varied in their methods, durations and outcomes. Some revolutions started with peasant uprisings or guerrilla warfare on the periphery of a country; others started with urban insurrection aimed at seizing the country's capital city. Revolutions can be inspired by the rising popularity of certain political ideologies, moral principles, or models of governance such as natio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spin (geometry)
Spin or spinning most often refers to: * Spin (physics) or particle spin, a fundamental property of elementary particles * Spin quantum number, a number which defines the value of a particle's spin * Spinning (textiles), the creation of yarn or thread by twisting fibers together, traditionally by hand spinning * Spin (geometry), the rotation of an object around an internal axis * Spin (propaganda), an intentionally biased portrayal of something Spin, spinning or spinnin may also refer to: Physics and mathematics * Spin group, Spin(''n''), a particular double cover of the special orthogonal group SO(''n'') ** the corresponding spin algebra, \mathfrak(n) * Spin tensor, a tensor quantity for describing spinning motion in special relativity and general relativity * Spin (aerodynamics), autorotation of an aerodynamically stalled aeroplane * SPIN bibliographic database, an indexing and abstracting service focusing on physics research Textile arts * Spinning (polymers), a process for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scalar (physics)
Scalar quantities or simply scalars are physical quantities that can be described by a single pure number (a ''scalar'', typically a real number), accompanied by a unit of measurement, as in "10cm" (ten centimeters). Examples of scalar are length, mass, charge, volume, and time. Scalars may represent the magnitude of physical quantities, such as speed is to velocity. Scalars do not represent a direction. Scalars are unaffected by changes to a vector space basis (i.e., a coordinate rotation) but may be affected by translations (as in relative speed). A change of a vector space basis changes the description of a vector in terms of the basis used but does not change the vector itself, while a scalar has nothing to do with this change. In classical physics, like Newtonian mechanics, rotations and reflections preserve scalars, while in relativity, Lorentz transformations or space-time translations preserve scalars. The term "scalar" has origin in the multiplication o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vector Quantity
In the natural sciences, a vector quantity (also known as a vector physical quantity, physical vector, or simply vector) is a vector-valued physical quantity. It is typically formulated as the product of a ''unit of measurement'' and a ''vector numerical value'' ( unitless), often a Euclidean vector with magnitude and direction. For example, a position vector in physical space may be expressed as three Cartesian coordinates with SI unit of meters. In physics and engineering, particularly in mechanics, a physical vector may be endowed with additional structure compared to a geometrical vector. A bound vector is defined as the combination of an ordinary vector quantity and a '' point of application'' or ''point of action''. Bound vector quantities are formulated as a '' directed line segment'', with a definite initial point besides the magnitude and direction of the main vector. For example, a force on the Euclidean plane has two Cartesian components in SI unit of newtons and an ac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seconds
The second (symbol: s) is a unit of time derived from the division of the day first into 24 hours, then to 60 minutes, and finally to 60 seconds each (24 × 60 × 60 = 86400). The current and formal definition in the International System of Units (SI) is more precise: The second ..is defined by taking the fixed numerical value of the caesium frequency, Δ''ν''Cs, the unperturbed ground-state hyperfine transition frequency of the caesium 133 atom, to be when expressed in the unit Hz, which is equal to s−1. This current definition was adopted in 1967 when it became feasible to define the second based on fundamental properties of nature with caesium clocks. As the speed of Earth's rotation varies and is slowing ever so slightly, a leap second is added at irregular intervals to civil time to keep clocks in sync with Earth's rotation. The definition that is based on of a rotation of the earth is still used by the Universal Time 1 (UT1) system. Etymology "Minute" ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Period (physics)
Period may refer to: Common uses * Period (punctuation) * Era, a length or span of time *Menstruation, commonly referred to as a "period" Arts, entertainment, and media * Period (music), a concept in musical composition * Periodic sentence (or rhetorical period), a concept in grammar and literary style. * Period, a descriptor for a historical or period drama * Period, a timeframe in which a particular style of antique furniture or some other work of art was produced, such as the "Edwardian period" * '' Period (Another American Lie)'', a 1987 album by B.A.L.L. * ''Period'' (Kesha album), an upcoming album by Kesha * ''Period'' (mixtape), a 2018 mixtape by City Girls * ''Period'', the final book in Dennis Cooper's George Miles cycle of novels * '' Periods.'', a comedy film series Mathematics * In a repeating decimal, the length of the repetend * Period of a function, length or duration after which a function repeats itself * Period (algebraic geometry), numbers that can be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Organization For Standardization
The International Organization for Standardization (ISO ; ; ) is an independent, non-governmental, international standard development organization composed of representatives from the national standards organizations of member countries. Membership requirements are given in Article 3 of the ISO Statutes. ISO was founded on 23 February 1947, and () it has published over 25,000 international standards covering almost all aspects of technology and manufacturing. It has over 800 technical committees (TCs) and subcommittees (SCs) to take care of standards development. The organization develops and publishes international standards in technical and nontechnical fields, including everything from manufactured products and technology to food safety, transport, IT, agriculture, and healthcare. More specialized topics like electrical and electronic engineering are instead handled by the International Electrotechnical Commission.Editors of Encyclopedia Britannica. 3 June 2021.Inte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International System Of Quantities
The International System of Quantities (ISQ) is a standard system of Quantity, quantities used in physics and in modern science in general. It includes basic quantities such as length and mass and the relationships between those quantities. This system underlies the International System of Units (SI) but does not itself determine the units of measurement used for the quantities. The system is formally described in a multi-part ISO standard ISO/IEC 80000 (which also defines many other quantities used in science and technology), first completed in 2009 and subsequently revised and expanded. Base quantities The base quantities of a given system of physical quantity, physical quantities is a subset of those quantities, where no base quantity can be expressed in terms of the others, but where every quantity in the system can be expressed in terms of the base quantities. Within this constraint, the set of base quantities is chosen by convention. There are seven ISQ base quant ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Number Of Rotations
The turn (symbol tr or pla) is a unit of plane angle measurement that is the measure of a complete angle—the angle Subtended angle, subtended by a complete circle at its center. One turn is equal to radians, 360 degree (angle), degrees or 400 gradians. As an angular unit, one turn also corresponds to one cycle (symbol cyc or c) or to one revolution (symbol rev or r). Common related Frequency#Unit, units of frequency are ''cycles per second'' (cps) and ''revolutions per minute'' (rpm). The angular unit of the turn is useful in connection with, among other things, electromagnetic coils (e.g., transformers), rotating objects, and the winding number of curves. Divisions of a turn include the half-turn and quarter-turn, spanning a Angle#Individual angles, straight angle and a right angle, respectively; metric prefixes can also be used as in, e.g., centiturns (ctr), milliturns (mtr), etc. In the International System of Quantities, ISQ, an arbitrary "number of turns ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
